This invention relates to a path-controlled window lifter of a motor vehicle.
Path-controlled window lifters are used for example for adjusting window panes for frameless doors of a motor vehicle, in particular for convertible cars. Beside the main adjusting movement in pull-off direction of the window pane, i.e. substantially in direction of the vertical or Z-axis of the motor vehicle, a guide path serves to guide a driver connected with the window pane and hence the window pane in direction of the Y-axis of the motor vehicle, i.e. vertical to the X-axis or longitudinal axis of the vehicle and Z-axis of the motor vehicle. The guidance in Y-direction of the motor vehicle is utilized to urge the window pane to the inside against a seal to completely close the window pane and thus to ensure a safe closing of the window pane. For this purpose, the path-controlled window lifter additionally can perform small adjusting movements in X- and Y-direction of the motor vehicle, which are defined by the course of the guide paths.
Such path-controlled window lifters have a large-surface base or base plate made of sheet metal, into which two or mostly three guide paths are stamped as profiled slots. Since the base plate is cut up in this way over the entire guide length, bridges are necessary on the one hand as a connection of both sides of the guide paths, and on the other hand the metal sheet must be designed thick-walled, in order to provide the base plate with the required stability and in particular inherent rigidity. In turn, this involves a high weight of the path-controlled window lifter and hence an undesired gain in weight of the motor vehicle.
From DE 101 44 777 A1 a path-controlled window lifter is known which includes a base plate mounted in the motor vehicle, which includes three guide paths for guidance and for adjustment of a driver along an adjustment path formed by the guide paths. The course of the individual guide paths is different, depending on the position into which the window pane is to be moved during the adjustment. To avoid breaking through the structure of the base plate, which would lead to a weakening of the mechanical stability of the base plate, which is required, however, to absorb the adjustment forces acting on the base plate, either the middle one of the three guide paths is put onto the base plate and forms an integral part of the base plate, or a guide path is fixed on the base plate as separate part by latching, screwing, bonding or press-fitting. The guide path formed as an integral part of the base plate is integrally connected with supporting structural elements of the base plate, so that the forces acting on the guide path can be absorbed by the structural elements of the base plate.
Furthermore, the base plate can be formed in several parts and the middle guide path can be integrated into a part of the base plate. As an alternative to an insert or outsert technique, a plastics-metal hybrid construction is proposed, in order to manufacture the structure of a multi-part base plate. Between the various parts of the base plate, attachments such as positive, non-positive or integral connections serve to increase the rigidity of the entire structure. For this purpose, a profiled metal sheet is at least partly overmolded by plastic material and reinforced by the ribs of the plastic material.